I take it your talkin' the MagPul brand. Not me but there are good reviews throughout the interweb. All Glock OEM is what I use. I saw the Glocks on sale a week or so back for <$20. ..... Not enough difference for me to NOT get OEM.
My Keltec Sub2000 9mm Glock Gen 2 (FDE) came with a 17rd p-mag. Seems to work very well. It does not have the little holes in the back to show you how many rounds are loaded. Would a buy a Glock p-mag probably not.